“Warming induced changes to body size stabilize consumer-resource dynamics”

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Matthew M. Osmond, Matthew A. Barbour, Joey R. Bernhardt, Matthew W. Pennell, Jennifer M. Sunday, and Mary I. O’Connor

Temperature-size response predicted to stabilize ecological communities under warming

Smaller bodies at hotter temperatures could stabilize ecological communities as climate warms

The temperature-size response is expected to stabilize consumer-resource systems under warming, meaning that plastic changes in predators like this backswimmer (Notonecta glauca) may improve their chance of persistence.
(Credit: Michelle Tseng)

Climate warming immediately impacts the metabolism of many species. From theory and experiments, scientists have deduced how such changes in metabolism will scale up to affect rates of birth, death, and food consumption. One important prediction stemming from this work is that climate warming is likely to destabilize interactions between a consumer species (e.g., a predator or herbivore) and its resource (e.g., a prey or plant). This drop in stability will cause larger fluctuations in in species’ abundances and ecosystem function when disturbed, and in extreme cases can lead to local extinctions.

A largely separate body of work examines the effect of temperature on the size of adult individuals. This includes what is known as the temperature-size rule, the observation that adult body size tends to decline with the temperature experienced during development. Since body size also affects rates of birth, death, and food consumption, climate warming will also impact the stability of ecological communities indirectly through changes in body size.

In their article appearing in The American Naturalist, a team of scientists from the Biodiversity Research Centre at the University of British Columbia in Vancouver, Canada, unite the influences of warming predicted by metabolic theory and temperature-body size scaling. Using a simple mathematical model, they find that the indirect effect of warming, through changes in body size, can stabilize consumer-resource systems and may even override the direct destabilizing effect of warming brought about by changes in metabolism. The increase in stability with temperature arises because within-species competition increases faster than the strength of between-species interactions as body sizes decline. Thus, the widely observed temperature–size rule may help maintain the structure and functioning of ecological communities as the climate warms and potentially prevent extinctions. Read the Article